Apparatus for drilling large diameter holes



Feb. 16, 1965 o. c. THATCHER 3,169,590

APPARATUS FOR DRILLING LARGE DIAMETER HOLES Filed Feb. 28, 1961 2Sheets-Sheet 1 INVENTOR. ORR/N GTHATcHEn ATTORNEYS Feb. 16, 1965 o. c.THATCHER 3,159,590

APPARATUS FOR DRILLING LARGE DIAMETER HOLES Filed Feb. 28, 1961 2Sheets-Sheet 2 INV EN TOR. Onnm C. THATCHER .AT TORNE Y3 United StatesPatent 3,169,590 APPARATUS FGR DRILLING LARGE DIAMETER HOLES Orrin C.Thatcher, Stanford, Mont. Ideas Inc, 2327 ltith Ave. 53., Great Falls,Mont.) Filed Feb. 28, 1961, Ser. No. 92,419 1 Claim. (Cl. 175-94) Myinvention relates to novel apparatus for drilling of cylindricalopenings of a given depth in the earths crust, for numerous purposessuch as underground silos or storage compartments, concealed gun mounts,imoedded missile pads and the like.

When drilling or forming openings for missile silos and the like, thevariations in hardness and kind of earth and rock formations (such assand, soft shale, limestone, hard rock, etc.) which may be locatedwithin the proposed opening often present problems which hinder theetficient drilling of the opening. Since portions of the relativelyheavy drilling head may be resting upon relatively soft ground and otherportions thereof may be on hard rock or the like, one of such problemsis that the support for the drilling head must be constructed so as toresist bending moments and stresses imparted thereto by portions of theheavy drilling head which are effectively cantilevered with respect tothe support.

The primary object of my invention is the provision of novel apparatusof the type immediately above described which overcomes the above notedproblems and which may be used to drill a cylindrical opening in therock formations of the earths crust of a greater diameter thanheretofore thought possible, and with a minimum of man-power andexpense.

A further object of my invention is the provision of apparatus of thetype above described which is not unduly expensive to produce and whichmay be installed in operative position and removed from a drilledopening with a minimum of skill and experience.

A still further object of my invention is the provision of apparatus ofthe type above described which is rugged and durable in construction andwhich requires but a minimum of maintenance.

The above and still further objects of my invention will become apparentfrom the following detailed specification, appended claim and attacheddrawings.

Referring to the drawings wherein like characters indicate like partsthroughout the several views:

FIG. 1 is a schematic view in vertical section, illustrating preliminarysteps in the practicing of my invention;

FIG. 2 is a view corresponding to FIG. 1 but showing my novel equipmentin side elevation and still illustrating further steps in the practiceof my invention;

FIG. 3 is an enlarged detailed vertical section of FIG. 2;

FIG. 4 is a View in horizontal section taken on the line 44 of FIG. 3;

FIG. 5 is a fragmentary view in section taken on the line 55 of FIG. 4;and

FIG. 6 is an enlarged fragmentary sectional view taken on the line 6-6of FIG. 3.

Referring with greater particularity to the drawings, the first step inmy method comprises the drilling of a vertical pilot hole A in theearths crust X, and for this purpose it is obvious that any suitablerotary rock drill bit may be utilized. For a purpose which willhereinafter be explained, it will be noted, by reference to FIG. 1, thatthe depth of the pilot hole A is greater than that of the proposedopening B to be drilled by my method and with my novel apparatus.

The next step in my method comprises placing into the vertical pilothole A an elongated, preferably cross-section cylindrical axle 1 thediameter of which, as shown in FIG. 1, is considerably smaller than thatof the pilot hole of the drilling head 5.

A. Furthermore, it will be noted that the axial dimensions of the axleit are such, with respect to the pilot hole A, that the upper end inthereof projects considerably above the surface of the ground X for apurpose which will hereinafter become apparent. After centering the axle1 within the pilot hole A, so as to define an annular space 2therebetween, the next step in my method resides in the anchoring of theaxle 1 within the pilot hole A. This may be done by the filling of saidspace 2 with concrete or grout 3, said grout 3 extending completely fromthe bottom 4 of the pilot hole A to the surface of the earth X. In thismanner the axle l is securely anchored within the earth X for thecarrying out of the remaining steps of my method with my novel apparatuseach of which is hereinafter described.

After suitable hardening of the grout 3, my novel drilling head,identified in its entirety by letter 5, is inserted over the extendedupper end in of the axle l, as shown in FIG. 2. By reference to FIG. 2,the problems presented by the portions of the drilling head 5 resting onrelatively soft ground may Well be appreciated. Drilling head 5 includesan annular horizontally disposed base plate 6, upstanding outside framemembers '7, and upstanding central tubular bearing sleeve 3, looselyencompassing the axle 1, and upper frame members or braces 9 connectingthe upper end portions of the outer frame member '7 of the bearingsleeve 3. Suitably journalled in bearing brackets it) depending from theunder surface 11 of the annular base plate 6, on axes radiating from theaxle l, are circumferentially spaced elongated roller bits 12 formed toprovide a plurality of generally axially extended circumferentiallyspaced cutting teeth 13. Rotary movements are imparted to roller bits 12by any suitable means but preferably through a pair of motors or powerunits 14 mounted on the upper surface 15 of the base plate 6.

' Since the particular design of the power units 14 is not an importantfeature of this invention, further showing and description thereof isunnecessary. Rotary movements of the roller bits 13 obviously irnpartrotary movements to the drilling head 5 in its entirety.

It will be noted by reference particularly to F168. 3 and 4 that thepower driven rotary bits 12 terminate at their axially inner endportions 16 in spaced relation to the axle 1 whereas their axially outerend portions 17 terminate in spaced relation to the outer peripherallimits 1% For the purpose of providing an uninterrupted cut betweenopposite side portions of the axle 1 and the outer peripheral edge 18 ofthe drilling head 5, I provide circumferentially spaced pairs of innergauge bits 19 and outer gauge bits Zil. As shown, the pairs of inner andouter gauge bits 19, 29, are spaced 180 with respect to each other andfrom the roller bits 12. The inner and outer gauge bits 1'9, Zll, arelikewise mounted for rotation on axes radiating from the axle 1, and areprovided with similar cutting teeth 13. The inner gauge bits 19 overlapthe cutting void between the axially inner ends 16 of the power drivenroller bits 12 and the axle 1, whereas the outer roller bits 29 overlapthe cutting void defined by the axially outer end portions of the rollerbits 12 and the outer peripheral edge 18 of the drilling head 5. Gaugebits 19, 2%, are preferably idlers.

Supplementing gravity so as to cause the drilling head 5 to exert thedesired amount of downward pressure upon the rock strata in which thedrilling head 5 is being worked, I provide means to exert a downwardpressure on the drilling head 5 relative to the anchored axle 1, and itwill be appreciated that the axle 1 must therefore be Well anchored toresist the relative pull thereon by such means. Said means isillustrated as comprising an adjustable anchoring collar 21 which isslidably receivable over the upper end la in overlying relationship tothe drill head 5. Anchoring collar 21 may be locked to the bearing 24 isjournalled for rotation on the tubular bearingsleeve 23 and rotativelyengages the under surface 25 of the anchoring collar 21. interposedbetween the thrust bearing 24- and the drill head 5 arecircumferentially spaced expandable and retractable elements which areshown as well known double-acting fluid pressure cylinder mechanisms,represented generally by 26, the same being provided so as to exert agenerally downwardly directed pressure on the drill head 5. As shown,the elements 26 include cylinders 27, the lower ends of which aresecured to the drill head 5, preferably and as shown through the mediumof the cross braces 9 thereof, as indicated at 21%.

Elements 26 likewise include pistons 29, the push rods of which areidentified by The upper ends of the rods 3t) are connected to the thrustbearing 24 as indicated at 31. Fluid under pressure is introduced intolower portions of the cylinders 27 to extend the cylinder 27, throughsuitable conduits 32 extending between the lower end portions of thecylinders 27 and suitable well known hydraulic reservoir and pump means,the latter of which is partially shown at 33 in FIG. 3 as being mountedon and carried by the drill head 5; It is noted that the reservoir andpump means partially shown at 33 in FIG. 3 is independent of the powerunits 14, the former however not being an important feature of thisinvention and therefore being only briefly described herein. Escape offiuid under pressure from the upper portions of the cylinders 27, so asto permit upward movements of the cylinders 27 and relative retractingmovements of the plungers 3%) carried thereby, is achieved through themedium of suitable tubes 34. The control of the operation 05 the fluidpressure cylinder mechanism 26 may be by any'suitable and well knownmeans, not shown.

Operation A drilling operation with my novel apparatus, assembled asshown in FIGS. 2 and 3, is as follows: With the push rods 30 retractedwithin their respective cylinders 27 the anchoring collar all is loweredinto engagement with the annular thrust bearing 24, and the collar 21 islocked in said position through the medium of set screws 22. Fluid underpressure is then introduced into the cylinders 27 by way of the pumpmeans 33 and the inlet tube 32, whereby to exert a predetermined amountof downward pressure of the drill head 5' against the underlying rockstrata comprising the earths crust immediately surround ing the axle 1.Rotary movements are then imparted to the roller bits 12 through themedium of the power units 14, whereby to impart rotary movements to thedrill head 5', as well as to the inner end idler gauge bits l9, 2%). Inthis manner an uninterrupted cut is effected between the axle l and theaxially outer limits 35 of the gauge bits 20. It will be understood thata constant amount of pressure is maintained within the cylinders 27 sothat a desired and constant downward pressure will be exerted by thedrill head 5 upon rock strata being drilled, as the drill head 5 worksits way downward therethrough. Obviously the precise amount of suchpressure will vary with the density of the rock'strata being drilled.

Removal'from the bottom of'the pit or opening B of the chi s and rockdust'loosened by the roller bits 12, 19, 20 may be effected by anysuitable and well known means. For instance, water may be introducedinto the bottom of the opening B-to form a Slurry, and removal of saidslurry etfected by a suction hose or the like, not shown.

It will be noted, primarily byv reference to FIG. 5, thatthe primaryfunction of inner roller gauge bits 19 is to drill and abrade awaythrough the concrete or grouting 3 about the axle 1. Thus, when thedesired depthof the opening B has been reached, the axle 1 is firmlysupported in a verticalposition by means of'the concrete or groutingSencompassing the lower end of the axle 1, below thebottom of theopening B.

While I have shown and described a workable form of my invention, I wishit to be specifically understood that the same may well be modifiedwithout-departure from the scope and spirit of the appended claim.

Whatl claim is:

Apparatusfor drilling into the earths crust a cylindricalopening of agiven depth for the formation of an underground silo or the like, saidapparatuscomprising an elongated axle of constant diameter andthe axialdimension of which is considerably greater than thatof the proposedopening, said axle beingadapted to be placed and secured within apreviously drilled centrally located vertical pilot hole of a verticaldepth greater thanthat of the proposed opening and with the upper endportion of said axle projecting above the upper elevation ofsaid'opening, a drilling head slidably rotatably received upon theprojectingupper end portion of said axle and having a drilling diametercorresponding to the desired-diameter of said opening, power operatedmeansfor imparting rotation to said head about said axle, and means forapplying a generally downwardly directed pressure on said drilling headrela-' tive to the upper end portion of said axle, said means forapplying a downward pressure on said drilling head comprising avertically adjustable anchoring collar slidably received upon andreleasably and adjustably secured to said axle in overlying relationshipto said drilling head, and a generally vertically extensible andretractable device interposed between said drilling head and saidanchoring collar.

References Cited in the file of this patent UNITED STATES PATENTS

